Wells are commonly used to access regions below the earth's surface and to acquire materials from these regions, for instance during the location and extraction of petroleum oil hydrocarbons from an underground location. The construction of wells typically includes drilling a borehole and constructing a pipe structure within the borehole. Upon completion, the pipe structure provides access to the underground locations and allows for the transport of materials to the surface.
During construction of a well, a borehole is often drilled in proximity to one or more existing wells. In some instances, it may be necessary to direct drilling away from existing well structures, such that the drill or the existing well structures are not damaged by a collision. Alternatively or additionally, it may be necessary to direct a drill alongside an existing well structure, such that the drill maintains a pre-determined distance from an existing structure. In some cases, it may be necessary to direct a drill towards an existing well structure, for instance during the construction to a relief well.
Moreover, in some instances it may be necessary to distinguish one existing well structure from another existing well structure. For instance, an operator may wish to drill alongside a specific well structure or drill towards a specific well structure, while maintaining sufficient distance between other specific well structures.
Thus, it is desirable to determine the location of existing wells and to distinguish existing wells from one another, to properly direct a drill during well construction.
Like reference symbols in the various drawings indicate like elements.